Medical conditions such as brain damage (stroke) and nerve damage (spinal cord injury) caused by accident or injury can result in the temporary loss or impairment of use of a subject's limbs. For example, the legs may be limited in their use such that the subject finds it difficult to walk. Following such injury or illness, a period of rehabilitation is typical during which nerve and/or muscle damage is repaired.
Such rehabilitation has been traditionally provided by a physiotherapist or physical therapist manually interacting with the subject. For example, the subject may walk on a treadmill or along a set path during which activity the physiotherapist will manually support and manipulate the subject's legs in order to provide the desired motion and feedback. By this process muscles and nerves can be gradually repaired.
Methods which involve the direct interaction of a physiotherapist, or require the physiotherapist to support and/or guide the subject are not ideal because they may result in uneven or unpredictable forces on the subject. It may also be uncomfortable for the therapist to undergo such activity for extended periods, potentially with numerous subjects. Fatigue or strength of the physiotherapist often is the limiting factor in therapy
An alternative to the above mentioned method is to provide a mechanical gait rehabilitation robot. Mechanical gait rehabilitation robots are known in the art.
WO2012/062283 discloses a device which uses a number of flexible cords in tension to support a subject's limbs during rehabilitation. Another example of such a device can be seen in U.S. Pat. No. 7,998,040. Although such devices can apply uni-directional forces to the subject (with the cords in tension), they are not able to provide forces in the opposite direction (a flexible cord cannot carry a compressive force), or in other directions (e.g. sideways to retain the subject's leg in a set path).
U.S. Pat. No. 6,666,798 discloses an apparatus for rehabilitation in which a therapist is connected to a subject via a set of rigid links. This system is provided to free the physiotherapist's hands, and still requires the physiotherapist to bear the weight of, and guide, the subject's legs. Therefore the inherent lack of repeatability and potential for injury to the physiotherapist is still present. The disclosure is also only concerned with lower leg rehabilitation, having the ankle and knee connected to the therapist. Therefore rehabilitation of the upper leg is not considered.
Prior art document CN101862255B discloses a known type of rehabilitation apparatus which has a mechanical leg at the side of the patient's leg. A problem with this type of apparatus is that it needs to be provided with extendible leg members in order to account for various different sizes of patient. As such, this apparatus is particularly complicated and time consuming to set up for each individual patient.